A car diffuser is a device designed to release pleasant scents into your vehicle's interior, helping to eliminate odors and create a more enjoyable driving environment. Unlike traditional air fresheners (like hanging trees or sprays), car diffusers often use essential oils, fragrance cartridges, or nebulizing technology for a more subtle, long-lasting release. They come in various forms, such as clip-on vent attachments, plug-in units, or portable USB-powered humidifiers, and many are smart-enabled to activate only when the car is in motion.